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On bird functional diversity: species richness and functional differentiation show contrasting responses to rainfall and vegetation structure in an arid landscape

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dc.contributor.author Seymour, CL
dc.contributor.author Simmons, RE
dc.contributor.author Joseph, GS
dc.contributor.author Slingsby, JA
dc.date.accessioned 2018-05-14T11:51:29Z
dc.date.available 2018-05-14T11:51:29Z
dc.date.copyright 2015-04-25
dc.date.issued 2015-04-25
dc.identifier.citation Seymour, CL, Simmons, RE, Joseph, GS & Slingsby, JA 2015, 'On bird functional diversity: species richness and functional differentiation show contrasting responses to rainfall and vegetation structure in an arid landscape’, Ecosystems, Vol. 18, No. 6, pp. 971-984, Viewed 14 May 2018, Springer Verlag, DOI: 10.1007/s10021-015-9875-8 en_US
dc.identifier.issn 1432-9840
dc.identifier.uri https://link.springer.com/article/10.1007/s10021-015-9875-8
dc.identifier.uri http://hdl.handle.net/10907/1879
dc.description.abstract Biodiversity affects ecosystem function through species’ functional traits. Although it is possible to predict species richness (SR) patterns along environmental gradients, whether functional diversity (FD) changes in predictable ways is not known. In arid environments, SR typically increases with rainfall. Aridity may limit functional differentiation by allowing only certain traits, but could also be associated with diverse traits associated with various strategies for coping with spatial and temporal variation in resources. Rare species may have unique traits, making them particularly important to continued ecosystem function. We investigated SR, FD, and functional differentiation in bird assemblages along an aridity gradient, with attention to functional uniqueness of rare species. We surveyed bird communities in open savanna, bush-thickened, and riparian habitats at five sites of increasing aridity (~150–400 mm rainfall year−1) in wet and dry seasons for 3 years in Namibia. We calculated the standardized effect size of FD (sesFD) as a measure of functional differentiation and used mixed models to ascertain how SR, FD, and sesFD relate to rainfall, season, and habitat type. SR and FD increased with increasing rainfall. Conversely, sesFD declined with increasing rainfall and was lower in woody habitats, suggesting habitat filtering and greater niche overlap. Rare species were more functionally unique than common species, in all three habitats, so loss of rare species could degrade ecosystem function. Our results are consistent with a linear diversity–productivity relationship maintained by regular disturbance (drought) preventing strong competitors from excluding weaker competitors in higher productivity environments. en_US
dc.description.sponsorship National Research Foundation (South Africa) en_US
dc.format.extent Tables: iv, fig.: iv, 14 p. en_US
dc.format.medium PDF en_US
dc.language.iso en en_US
dc.publisher Springer Verlag en_US
dc.rights Attribution-NonCommercial-NoDerivs 3.0 United States en_US
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/us/ en_US
dc.subject Aridity gradient en_US
dc.subject Bush encroachment en_US
dc.subject Bush thickening en_US
dc.subject Environmental gradients en_US
dc.subject Environmental filtering en_US
dc.subject Functional uniqueness en_US
dc.subject Null models en_US
dc.subject Rare species en_US
dc.subject Shrub encroachment en_US
dc.subject Standardized effect size en_US
dc.title On bird functional diversity: species richness and functional differentiation show contrasting responses to rainfall and vegetation structure in an arid landscape en_US
dc.type Article en_US
dc.rights.holder Springer Verlag en_US


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